The major objectives of the proposed research are twofold: 1) The isolation, purification, and study of the mechanism of reaction of three sialyltransferases (embryonic chicken brain, cat bone marrow and bovine spleen), three galactosyltransferases (embryonic chicken brain, porcine brain, and rabbit serum), and one glucosyltransferase which are involved in the biosynthesis of neutral glycosphinglipids, gangliosides and cerebrosides. The subcellular distribution of these enzymes in normal tissues (brain, bone marrow, and spleen) will be determined. Once the methods hve been established, further studies of these enzyme levels in human normal and pathological tissues will be made. 2) Biosynthetic studies in vitro of globoside, Forssman hapten, and blood group B-, A-, H-, and Lea-active glycosphingolipids in rabbit, guinea pig, human, and sheep bone marrow cells will be continued and extended, with a view to determining the presence of these compounds on the cell surface and their possible role in the cellular interaction and plant lectin binding. The final stage of this investigation will involve biosynthetic studies in vitro of blood group active glycosphingolipids in human bone marrow (and serum) of different blood types.